"certain fields of all records"?
You mean if a field is set to "send email" of every record in the table, send an email? Or just one record has a specified field modified triggers sending an email to a designated recipient?
In my table, every record has three UPC codes. If any one of those UPC codes are modified in any record I want an email to be sent to specific email addresses if I have "Notification" field set to "Yes" for that record. Does that make sense and answer your question?
Yes, that clarifies.
If you are using a FileMaker 10 or newer and not via Instant Web Publishing to modify the code fields, you can set an On ObjectSave script trigger on each that would send such an email. This same script could also log data in a related table (can store current UPC code as well as account info on the user, date time etc.) so that this info can be part of the email sent out.
Thus, a send mail script step performed by this trigger can send out an email stating: "Item 235's UPC code was changed from ABC to ABD by Jim Johnson on October 31, 2010..."